20122338http://ejcp.gau.ac.ir/article_430_468f8402819b040cf93236efde82b05b.pdfEvaluation of non-Linear regression models to predict stem elongation rate of wheat ((Tajan cultivar) in response to temperature and
Photoperiodtextarticle2012perThe first step to quantify crop phenology is precise estimation of the parameters, which affect it. These parameters are mainly temperature and photoperiod. This study was conducted with eight sowing dates to quantify response of stem elongation rate (SER) to temperature and photoperiod in wheat (Tajan Cultivar). The regression models fitted to SER against temperature were flat, logistic, quadratic, cubic, dent-like, segmented and curve models. Meanwhile, quadratic, negative exponential and segmented models fitted to SER against photoperiod (these models were used as 21 combined models to describe SER as a function of photothermal day). Root mean square of errors (RMSE), coefficients of determination and regression coefficients of predicted values versus observed ones were used to find the most appropriate model. The results showed that segmented-segmented function was the best model to describe SER as a function of both temperature and photoperiod. Using this function, the base and optimum temperatures, critical photoperiod and photoperiod sensitivity coefficient were estimated as 4.14 ˚C, 28 ˚C, 14 h and 0.17, respectively. Study the effects of temperature and photoperiod on stem elongation phase indicated that Tajan cultivar has a quantitative or facultative long-day (LDP) response to photoperiod. Biological days required to pass from emergence to stem elongation and emergence to physiological maturity were estimated as 7.66 and 50.31, respectively.مجله تولید گیاهان زراعیدانشگاه علوم کشاورزی و منابع طبیعی گرگان و انجمن زراعت و اصلاح نباتات ایران2008-739X2

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20123954http://ejcp.gau.ac.ir/article_431_0d9492f6d889be12b45763e882a022fd.pdfEffects of acclimation on wheat (Triticum aestivum L.)
cold tolerance under laboratory conditionstextarticle2012perSever coldness causes damage to the wheat and affect its growth and yield, thereby this experiment was conducted in controlled conditions to investigate freezing tolerance of 29 wheat genotypes. Acclimation treatments (in two levels: acclimation and non-acclimation) were considered in the main plot and combination of temperature (0, -4, -8, -12, -16 ◦C) and genotypes as sub plot. Survival percentage, dry weight and plant height were measured four weeks after freezing in the glasshouse. All these traits were affected significantly by freezing treatments (Pمجله تولید گیاهان زراعیدانشگاه علوم کشاورزی و منابع طبیعی گرگان و انجمن زراعت و اصلاح نباتات ایران2008-739X2

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20125570http://ejcp.gau.ac.ir/article_432_10be9489b6b692440832d898caa7e277.pdfThe Effect of Nitrogen Rate and Weeding Time on Weed Communities Dynamic and yield of Canola (Brassica napus L.)textarticle2012perIn order to evaluate the effect of nitrogen rate and weeding time on weed communities dynamic, a field study conducted in a research farm of Chamran University, Ahwaz. The experimental design was split plot based on RCB with three replications. Nitrogen rates (77, 110, 143 kg/ha) were considered in the main plot and time of weeding (at 5, 8, 11, leaf stage with control and weedy plot) as sub plot. The effects of treatments on weeds were evaluated at two periods: the first period was each time of weeding and the second one was before canola harvesting. The results indicated that nitrogen rate and weeding time had significant effect on weed dry matter and density. The highest weed dry matter with 482 g.m-2, was obtained from 143 kg N.ha-1 and weedy check and the highest weed density with 292 plant.m-2 was obtained from 77 kgN.ha-1 and weeding at 8-leaf stage. In the most cases, weed dominant species, frequency and phenological stages were affected by treatments. However, the effect of nitrogen rate and weeding time at the first period was higher than other treatments. The highest grain yield with 4740 Kg.ha-1 was obtained from 143 kg N.ha-1and weed free plots. Therefore, canola gain yield was increased with increasing of nitrogen rate.مجله تولید گیاهان زراعیدانشگاه علوم کشاورزی و منابع طبیعی گرگان و انجمن زراعت و اصلاح نباتات ایران2008-739X2

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20127192http://ejcp.gau.ac.ir/article_433_891a38244ca51a43f0b4b071dc2d6685.pdfPhysiological responses of different wheat genotypes to cold stresstextarticle2012perIn order to determine yield and physiological response of different wheat genotypes to low temperature, many pot and field experiments were conducted in 2007-2008 at the Plant Physiology Laboratory, University of Kurdistan, and Ghamlo Dryland Agricultural Research Station in Kurdistan province. In both experiments, the experimental design was a randomized complete block in a split plot arrangement with three replications. Experiment was carried out in 2007. Corresponding to three field sowing dates, Oct 1th, Oct 16th and Nov 5th, three pot treatments were performed. Pot treatments were conducted at following temperatures: 20 (control), 10 and 5 °C. Temperature treatments were considered in main plot and twelve genotypes of dryland wheat were assigned to the sub-plots. Both in pot and field experiments, leaf chlorophyll and sugar contents, fatty acids, polyamines and leaf water were significantly affected by treatments. When protein, spermine and oleic acid were measured, no differences were evident among genotypes. Cold stress and genotype had significant effects on the lethal temperature 50 (LT50) and electrolyte leakage. Among the genotypes, Ogosta exhibited the highest cold resistance (LT50), and the lowest electrolyte leakage. Also, Sardari and Ogosta had the greatest grain yield (1178-1210 kg.ha-1), chlorophyll a, chlorophyll b, soluble sugars, protein, putrescine, spermine, spermidine, linolenic acid and oleic acid.مجله تولید گیاهان زراعیدانشگاه علوم کشاورزی و منابع طبیعی گرگان و انجمن زراعت و اصلاح نباتات ایران2008-739X2

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201293112http://ejcp.gau.ac.ir/article_434_0e0ed1e44a35109b272c4447be76bf39.pdfResponses of yield and yield components of three safflower
(Carthamus tinectorious L.) spring cultivars to salinity
induced at different growth stagestextarticle2012perSalinity stress is one of the most important environmental constraints that have been limited agricultural production in Iran. Therefore, introducing suitable cultivars having desirable yield under salinity stress will lead to increase of production efficiency. In order to study the response of spring safflower cultivars to salinity, an experiment was carried out at the Experimental Station of the University of Birjand during 2007. The study was done as a split-plot experiment based on a Completely Randomized Block Design with three replications. Treatments were three times of salinity application (at branching, budding, and flowering) as main plots and three cultivars (Mahali Isfahan (a local variety), PI, and IL111). Salinity stress was induced using well water with an EC equal to 8.6 dSm-1. Results showed salinity had non-significant effects on yield components of cultivars, but the effects followed by these small changes influenced seed and oil yields and oil percentage significantly by time of salinity exertion. There was a significant difference between cultivars in yield and also the most of yield components, with notable superiority of Mahali Isfahan over PI and IL11. Slicing of interactions of cultivars in each time of saline water application indicated that majority of differences between cultivars was related to their response to salinity induced at budding, with Mahali Isfahan had the highest seed weight and seed number. than others. In general, it seems that Mahali Isfahan cultivar had more adaptability to irrigation with saline water. If this cultivar is irrigating with fresh water during reproductive phase, especially between budding to full flowering, it can producea reasonable seed and oil yields.مجله تولید گیاهان زراعیدانشگاه علوم کشاورزی و منابع طبیعی گرگان و انجمن زراعت و اصلاح نباتات ایران2008-739X2

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2012113134http://ejcp.gau.ac.ir/article_435_ad6137e61278fc7bfc6c1ae7c9bb957c.pdfAssessment of genetic diversity and relationships between seed traits in tall fescue populations using multivariate statistical analysistextarticle2012perSeed production, as well as other economical and ecological attributes, is an important character in grasses. Knowledge on the genetic diversity of seed yield and yield components on Iranian tall fescue accessions, as a high productive and adaptive grass is limited. This experiment was conducted to investigate the genetic diversity of seed yield and seed components, determine relationships between traits and identify components of seed yield in 46 tall fescue accessions using some multivariate statistical methods under field conditions. Results indicated that there is a broad genetic diversity in this germplasm for seed yield and its components, which can be employed in breeding programs. Correlation coefficients of seed yield with all measured traits were positive and significant and the highest one was found for seed per plant (0.91). Seed yield was positively correlated with flag leaf width and length. Results of factor analysis showed that to seed yield in tall fescue, not only size and efficiency of reproductive system, but also flag leaf characters are important. Based on regression methods, in an indirect selection index, the efforts should be focused on panicle per plant and panicle fertility.مجله تولید گیاهان زراعیدانشگاه علوم کشاورزی و منابع طبیعی گرگان و انجمن زراعت و اصلاح نباتات ایران2008-739X2

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2012135148http://ejcp.gau.ac.ir/article_436_5483635d8082ccc076b697cebae247ed.pdfEvaluation of resistance and response of grain yield and yield components of spring wheat genotypes to Fusarium Head Blighttextarticle2012perFusarium head blight (FHB) is an important disease in wheat worldwide that reduces grain yield, quality as well as contaminates grains to the mycotoxins. Thirty spring wheat genotypes including 28 bread wheat and two durum wheat genotypes were evaluated for FHB under a randomized complete block design with three replications. Grain yield and its components were evaluated by using two environmental conditions including disease-free environment (created by Tilt fungicide) as a control and disease-infested environment by hand sporing. The disease incidence (DIC), disease severity (DSV), Fusarium damaged kernels (FDK) and stress susceptibility index (SSI) were evaluated as four types of resistance indices. Combined analysis showed the significant reduction of grain yield via grain weight that was affected by FHB. The bi-plot diagram for ISK (Incidence-Severity-Kernels) and SSI (Stress Susceptibility Index) showed that the Falat cultivar was the most susceptible and Sumi3 and Frontan were two most resistant cultivars to yield reduction.مجله تولید گیاهان زراعیدانشگاه علوم کشاورزی و منابع طبیعی گرگان و انجمن زراعت و اصلاح نباتات ایران2008-739X2

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2012149166http://ejcp.gau.ac.ir/article_437_db0ab8e60ba1f704107b8dcad28a946d.pdfEffect of different amounts of foliar- and soil- applied N on
yield and yield components of promising bread wheat
(Triticum aestivum) lines in Gorgantextarticle2012perEffect of different amounts of foliar- and soil- applied N were evaluated in a factorial arrangement of RCBD with three replications at the Agricultural Research Station of Gorgan in 2004-2005 growing season. Two promising lines of bread wheat, two levels of foliar application of nitrogen (0 and 5%) at tillering and booting stage, with five rates of 0, 45, 90, 135 and 180kg N/ha as urea were used. ANOVA results showed that grain and biological yield increased from 4130 and 9529 kg/ha to 5399 and 13400 kg/ha at 0 and 180kg N/ha, respectively. Foliar application of nitrogen did not affect grain yield of studied lines. Grain yield was not significantly affected by N foliar application, while it increased yield about 120 kg.ha-1. With increasing of N rate, spike length increased significantly. Increasing of grain yield due to soil-applied N might be attributed to increase in number of seeds per spikes.مجله تولید گیاهان زراعیدانشگاه علوم کشاورزی و منابع طبیعی گرگان و انجمن زراعت و اصلاح نباتات ایران2008-739X2